I have owned both the Olympus 40-150 F4 and the Panasonic 35-100 F2.8. In my opinion they both are fantastic lenses. Either one of them is a great add to your kit.
I got my first camera ( Kodak Retina 1A ( in 1958 and have had a few cameras and lenses of varying format and quality. These days M4/3 good quality lenses are very sharp from wide open and diffraction seems is just about evident beyond f8. My experience with my Olympus 40-150 f4 on my OM5 is that it is sharp from wide open and has good contrast when printing A3+ on a Canon Pro 100s. It is not sensible to comment on lens quality using a very small jpg file and no good will come from using such a small file for that purpose. I think you will find that very small jpgs from asana 35-100 f2.8 will also be pretty bad.
